MIPS: fix endianess handling

Make endianess of target CPU configurable. Use the new config
option for dbau1550_el and pb1000 boards.

Adapt linking of standalone applications to pass through
endianess options to LD.

Build tested with:
 - ELDK 4 mips_4KC- and mips4KCle
 - Sourcery CodeBench Lite 2011.03-93

With this patch all 26 MIPS boards can be compiled now in one step by
running "MAKEALL -a mips".

Signed-off-by: Daniel Schwierzeck <daniel.schwierzeck@googlemail.com>
diff --git a/README b/README
index c98afa7..9702067 100644
--- a/README
+++ b/README
@@ -374,6 +374,12 @@
 		Defines the string to utilize when trying to match PCIe device
 		tree nodes for the given platform.
 
+- Generic CPU options:
+		CONFIG_SYS_BIG_ENDIAN, CONFIG_SYS_LITTLE_ENDIAN
+
+		Defines the endianess of the CPU. Implementation of those
+		values is arch specific.
+
 - Intel Monahans options:
 		CONFIG_SYS_MONAHANS_RUN_MODE_OSC_RATIO